Bucking bar for tubular members



OC' 17, 1944- A. H. HABERSTUMP -BUCKING BAR FOR TUBULAR MEMBERS FiledDec. 17, 1942 Y HZfreJ/Y Haier Patented Oct. 17, 1944 VBUCKING BAR FORTUBULAR MENEBERS Alfred H. Haberstump, Detroit, Mich. assigner to TheMurray Corporation of'America, Detroit, Mich., a corporation of DelawareApplication December 17, 1942, Serial No. L169,321

9 Claims.

This invention relates to bucking bars and particularly to a new andnovel bucking bar employed for bucking arivet on the inside of tubularelements.

When the rivets which extend through the wall of a tubular'element ofsmall 'diameter are to be bucked, diculty has been experienced inpositioninga dolly within the element in position to engage and buck therivet. Especially is this true when the rivets have their heads on theoutside of the tube and are driven from the outside in the manneremployed in the aircraft industry. While some types of bucking bars havebeen heretofore constructed to back the rivets which extend through atubular wall, these, as far as applicant knows, are not entirely suc`cessful because of the fact that the same reaction is not obtained atall points throughout y the length of the bar.

Following the teaching of the copending application to A. H. Haberstump,Serial No. 440,837, led April 28, 1942, and assigned to the assignee ofthe present invention, the bucking bar of the present invention issupported in parallelogram relation to the base so that the samereaction is obtained at all points throughout the bar length. The barmay span `any number of rivets and the entire number is swaged withoutthe necessity of moving the bar from one rivet to another as the samereaction'will obtain at all points along the bar. This is necessary whenemploying a, timing device on the percussion hammer such as thatillustrated and described in the copending application of A. H.Haberstump, Serial No. 439,115, led April 15, 1942, and assigned to theassignee of the present invention. This timing device controls thenumber of strokes struck by the hammer during the cycle and when buckedin they same manner identical bucktails willbel swag'ed on the endsof'all of the rivets being driven. If the bar would react differently at`points throughout its length, it Ywill be readily apparent thatdiierentswaging operations would be performed on the vrivets when struckthe same number of times" andthe bucktails produced engagement with theinner wall of thevtube. Onl-y suicient pressure is employedwhen'raising-thef'bar so that it may be deected by# a rivet-when forceddownwardly by: the operator when applying the riveting hammer to therivet head As the hammer operates, the-'impact is applied through therivets tothe barv which swages the end as the bar' is-maintained againstthe rivet by the applicationl of the force on one of its ends. Thecylinder is connected to a flexible conductor by which the bucking baris advanced along the wall. Air is introduced into thecylinderthroughtheconductor to'moVe-/the piston outwardly for Amoving and holding` thebucking bar against thel wall of the tube-ortho rivet ends. When therivet is forced downwardly to have its head engage the surfacev of theouter element to be riveted, the bar is deflected against y the pistonAwhich isforced back against theA pressure in the cylinder.

Accordingly, theA main objects of this inventionrare:y to provide abucking bar for a` tube having a base element and a buckingelement inparallel relation toeach otherinterconnected by parallel links which arein pivotal relation therewith'and manipulate the baron the links with apiston in aligned relation with the bar; to form a bucking bar 'from abase element which is a channel-shaped stamping having bosses forpivoting links on which a solid bucking bar is pivote'd and'lcontrolledby a piston and cylinder mounted' on the end of the base to whichfpres'-sure is delivered by a flexible conductor by which theb'ucking bar ismanipulated in a tube torbe riveted; to construct a compact bucking barfrom a channel element and a T-shaped bar which are interconnectedby apair of links to produce parallelogram relationship therebetween andvprovide a flexible conductor at the end "of the bar for applyingpressure thereto; and in general to 'provide acompact buckingv bar whichis `in sertable within a tubular element of small diam- `eter,'which issimple in construction, positive'in in Figure 1, with parts in sectionand with the bar in raised operating position;

Figure 3 is a sectional view of the bucking bar illustrated in Figure 1,taken on 4the line 3 3 thereof; and

Figure 4 is a sectional view of the structure illustrated in Figure l,taken on the line 4-4 thereof.v Y

The bucking bar embodies a base element I which is of channel sectionhaving bosses Il welded or otherwise secured near opposite ends thereof.The forward end of the bar is arched upwardly at I2 while the rear endis extended at I3 and flanged upwardly at I4 lto form a rear wall havingan aperture I5 therethrough. A pair of links I6 are pivoted at one endto the bosses II,by the pins I1 while the opposite ends are pivoted bythe pin I8 to the bucking element I9. The element I9 is provided withrecesses 2I for receiving the links and cutaway portions 22 and 23 forreceiving the bosses I I.

The bucking element I9, as illustrated in Figs. 3 and 4, is T-shaped insection having an enlarged head 24 which engages the rivets. The elementI9 is retained at all times parallel to the base element I0 because ofits support on the links I6 and will produce the same reaction in thecentral as well as the overhanging end portion thereof. The samereaction is obtained for swaging the bucktails on the rivets at allpoints throughout the bar length as when the hammer is operated on apredetermined time cycle assurance will be had that all of the bucktailsformed on the swaged rivets will be exactly of the same diameter andthickness.

vFor applying resilient pressure to the bucking bar while retaining thebar compact so as to be insertable in a tubular element of smalldiameter, a cylinder 25 having a threaded stem 26 is mounted in theextending end portion I3 of the base element I0 with the threaded stemextending through the aperture I5 and secured in position by a nut 26.iA hose connector 28 is threaded within the stem 26 and a hose 29 issecured thereto by suitable means, herein illustrated as by a clamp 3|.A piston 32 extends within the cylinder 26 and is sealed thereto by asealing cup 33 of conventional form which is retained in position by awasher 34 and a screw 35. The outer end of the piston 32 has an arcuatehead 36 which provides point engagement with vthe end of the buckingelement I9 which permits the bucking element to move across the headwithout material resistance. It is to be understood that while thepiston herein illustrated is to be operated by fluid pressure, that aspring could be employed within the cylinder 25 for operating thepiston, the tension on which may be applied by the movement of a wire orrod through the hose 29.

In Figure 1, the bucking bar is illustrated with the piston retractedwithin the cylinder 25 and the bucking element I9 moved downwardly ontothe base element I0. In this position, the bar is readily insertedwithin the tubular element, such as 31, to which an element 38 is to beriveted. After the bar has been `inserted sufficiently to engage aplurality of the rivets, air is applied to the cylinder 25 through thehose 29 to move the piston to the left, as viewed in the ligure, tothereby move the bucking element I9 upwardly on the links I6 intoengagement with the inner surface of the tubular element or to thebucktail of rivets which have already been driven.

A rivet, such as 39, is inserted in an aperture through the elements 38and 31 and the driving dolly 4I of a riveting hammer is placed againstthe head of the rivet forced downwardly to push the head of the rivetinto engagement with the outer surface of the element 36. This deectsthe bucking element I9 which reacts against the piston 32 to move thepiston against the pressure of air within the cylinder 25. As thedriving hammer is operated, the impact applied to the rivets causes theend thereof to become swaged as the bucking bar is constantly urgedagainst the end thereof, so that after a predetermined time cycle abucktail 42, such as that illustrated in Fig. 2, is formed on the end ofthe rivet.

All of the rivets which can be spanned by the bucking element I9 aredriven in this manner and like bucktails 42 will be formed on all of theends thereof because of the exact reaction to the bucking operation bythe bucking bar at all points along its length. Thereafter, pressure isremoved from the cylinder 25 permitting the piston 32 to retract as thebucking element I9 moves downwardly upon the base element I0. Thebucking bar may be moved further within the tube thereafter to span anadditional group of the rivets to be swaged. Air will again be appliedthrough the hose 29 into the cylinder 25 to again advance the piston andthe bucking element I9 into engagement with the inner surface of thetubular element 31. By marking the hose 29, the position of the buckingbar I0 on the inside of the tube can readily be ascertained and thebucking bar can be accurately located in this manner.

What is claimed is:

1. A bucking bar comprising, a base element, a pair of links pivoted tosaid base element, a bucking element pivoted on the end of the links, acylinder supported by the base element in aligned relation to saidbucking element, and a piston in said cylinder in abutted engagementwith one end of the bucking element.

2. A bucking bar comprising, a base element, a pair of links pivoted tosaid base element, a

bucking element pivoted on the end of the links,

a Cylinder supported by the base element in aligned relation to saidbucking element, a piston in said cylinder contacting the buckingelement, and a flexible hose connected to the cylinder.

3. A bucking bar for a hollow tube including, a base element of channelsection, bosses provided within the' channel element, links pivoted tosaid bosses, a bucking element supported within the channel on the pairof links, a cylinder supported by the channel element beyond one end ofthe bucking element, and a piston within said cylinder movable intoengagement with the end of said bucking element.

4. A bucking bar for a hollow tube including, a base element of channelsection, bosses provided within the channel element, links pivoted tosaid bosses, a bucking element supported within the channel on the pairof links, a cylinder supported by the channel element beyond one end ofthe bucking element, a piston within said cylinder movable intoengagement with the end of said bucking element, and a flexible uidconductor secured to the end of the cylinder for conducting pressurethereto and'for manipulating the bucking bar within the hollow tube.

5. A bucking bar for a tubular element embodying a base element-comprising a stamping of channel section having an upwardly archedfront end portion and an upwardly extending rear portion having anaperture, a cylinder in the rear portion having a hollow extending stemprojecting through said aperture and secured thereto, a T-shaped buckingbar having recessed portions, a pair of links each pivoted within arecess, pivots for interconnecting the opposite ends of the links to thebase element, and a piston within said cylinder for operating theT-shaped bucking element.

6. A bucking bar for a tubular element em- .bodying a base elementcomprising a stamping of channel section having an upwardly arched frontend portion and an upwardly extending rear portion having an aperture, acylinder in the rear portion having a hollow extending stem projectingthrough said aperture and secured thereto, a T-shaped bucking bar havingrecessed portions, a pair of links each pivoted within a recess, and apiston within said cylinder having an arcuate end which abuts againstthe end of the bucking element.

7. A bucking bar for a tubular element embodying a base elementcomprising a stamping of channel section having an upwardly arched frontend portion and an upwardly extending rear portion having an aperture, acylinder in the rear portion having a hollow extending stem projectingthrough said aperture and secured thereto, a T-shaped bucking bar havingrecessed portions, a pair of links each provided Within a recess, apiston within said cylinder having an arcuate end which abuts againstthe end of the bucking element, and a flexible conductor secured to theend of the cylinder for conducting air to the piston and formanipulating the bucking bar within the hollow tubular element.

8. A bucking bar embodying a base element which is a channel-shapedstamping, spaced links supported on said base element, a bucking elementpivoted on said links to provide a parallelogram relationship betweenthe bucking element and the base element, and resilient means supportedat one end of the base element in alignment with said bucking elementfor urging the bucking element upwardly on the links and provide apredetermined pressure thereto.

9. A bucking bar embodying a base element which is a channel-shapedstamping, spaced links supported in said base element, a bucking elementpivoted on said links to provide a parallelogram relationship betweenthe bucking element and the base element, resilient means supported atone end of the base element in alignment with said bucking element forurging the bucking element upwardly on the links and provide apredetermined pressure thereto, and a flexible extension on said buckingbar through` which the pressure on said bucking element is adjusted.

ALFRED H. HABERSTUMP.

